Stock options (Details 3)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
SBCE recognized related to:
Stock options	432,000	492,000	265,000
Preferred Share Rights (see note 8)	226,000NSFDF_PreferredShareRights
Total SBCE	658,000NSFDF_StockbasedCompensationExpense	492,000NSFDF_StockbasedCompensationExpense	265,000NSFDF_StockbasedCompensationExpense

The number of shares reserved for issuance pertaining to the outstanding exercisable stock options as of the balance sheet date in the customized range of exercise prices for which the market and performance vesting condition has been satisfied.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(iii)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant